1. Technical Field
The present invention relates to an absorbent article of pants-like shape, such as incontinence pants, pants diapers or sanitary towel pants, comprising an elastic waist portion, an absorbent element, which has a length and a width and is intended to at least cover the genitals of the wearer during use of the article. The invention also relates to a method of manufacturing such absorbent articles of pants-like shape.
2. Background Art
Absorbent disposable products for taking up urine, feces or menstrual blood have developed greatly since they came into more general use during the 1960s and 1970s. As they are disposable products, it is necessary that they can be manufactured and sold at a very low price. At the same time, it is important that the products function well and reliably. Good fit and comfort are also important characteristics. The first disposable diapers were made of two-part products, consisting of an outer pant made of plastic, intended to be re-used, and a rectangular absorbent insert for disposable use. The absorbent material in these inserts initially consisted of cellulose tissue. Later, better absorption materials made of what is known as fluff pulp made of cellulose were developed. The fit and comfort of these early diapers were poor. The products were unwieldy and uncomfortable for the wearer. Towards the end of the 1970s, the first complete disposable diapers arrived, that is to say diapers in which the absorption bodies were integrated with a liquid-impermeable outer layer. The absorption materials have developed and improved, which has resulted in the possibility of the absorption bodies being adapted better to the anatomy of the wearer. Hourglass-shaped absorption bodies with a narrower crotch portion between the two end portions are now predominant. The trend has also been towards increasingly thin products, which has been made possible by the inclusion of what are known as superabsorbent materials in the absorption body. There are many reasons why thinner and even smaller absorption bodies are desirable. A thinner, smaller absorption body is more comfortable and more discreet, which is especially important for adult incontinent wearers. A reduction in volume is also very important financially because the product then requires less storage space and is easier to transport and takes up less shelf space in shops. This is important for the financial management of the shops, and if a manufacturer can produce products requiring less space in the shops than the products of the competitors, this affords a not inconsiderable competitive advantage. Moreover, there is increased pressure from authorities, in particular as far as disposable articles are concerned, to use as little material as possible for the purpose of reducing the burden on the environment.
The smaller the absorption bodies become, the more important it becomes that the absorption bodies come to lie in the correct place directly in front of the genitals of the wearer and remain in place during use even when the wearer is very active and moves a great deal. The demands of consumers for discretion, comfort and reliable functioning are also increasingly exacting. Requirements for the absorption body to come to lie correctly when put on and then be retained in the correct place have therefore increased the need for good fixing of the article on the body and the need for very good adaptability to the body when the wearer moves, at the same time as requirements have increased for the article always to come to lie in the correct place when the article is put on the wearer. This has led to the development of what are known as pants diapers, which have elastic portions for improved fit and comfort and increased flexibility during movements of the wearer compared with conventional absorbent articles.
An early patent publication relating to pants diapers of the disposable type is GB 2 112 267-A. However, this publication from 1983 discloses primitive pants diapers which did not become a commercial product. Not until the 1990s did absorbent articles of pants-like shape and construction become a major commercial product. Pants-like articles now exist in the form of diapers for infants and diapers for adults and to some extent sanitary towel pants for absorption of menstrual fluid. Previously commercially available pants diapers have been designed in principle like conventional diapers with a front portion and a rear portion and also an intermediate crotch portion, the front and rear portions being interconnected by a side seam between each leg opening and the waist opening of the pants. The pants diapers have been produced by plane diaper-like pieces being produced in a continuous web, the individual pants diapers being formed by diaper-like blanks being folded double and provided with said side seams to form pants diapers. These side seams project laterally from the finished product and are undesirable because they project and interfere with the fit of garments worn over the top. On account of their shape, they are visible through garments worn on top of the pants diapers and fitting closely around the body. They can also snag in clothing and even cause tears in nylon tights. Such projecting side seams can also chafe and give rise to pressure sores on wearers who spend a lot of time lying on their side.
WO 00/61049 has proposed improved pants diapers, in which the projecting sides seams have been eliminated. In this construction, the side seams have been eliminated by virtue of elastic side portions extending continuously in one piece from the front portion of the pants diapers to their rear portion on both sides of the pants diapers. However, the pants diapers according to WO 00/61049 have a number of disadvantages. The pants diapers according to said publication have what is referred to as a chassis, which extends over the entire pants diapers and forms the front portion, the crotch portion and the rear portion and is most reminiscent of a conventional diaper, and also said elastic side panels which each overlap the chassis at both the front and the rear on the pants diapers. These overlapping portions do not serve any actual purpose on the finished product and are in fact undesirable because a lot of material is wasted, that is to say they are used for no other purpose than joining together. The overlapping, joined-together portions are less of a nuisance and less uncomfortable for the wearer than the projecting side seams on previously known pants diapers. Owing to their unfavorable positioning, particularly at the rear, the overlapping portions can still give rise to a risk of chafing and back sores on wearers who spend a lot of time lying on their back. Another disadvantage of the pants diapers according to WO 00/61049 is that said chassis is relatively large and, as this portion is relatively rigid at least in comparison with the elastic side portions of the pants diapers, the pants diapers as a whole are not as adaptable to the body of the wearer but there is a risk that the pants diapers will be displaced from their optimum position in relation to the body when a wearer lies in bed and moves. In particular the rigid rear portion of the pants diapers can be displaced and pull both the crotch portion and the front portion from their optimum positions directly in front of the genitals of the wearer because the front and rear portion are essentially rigidly joined together in one piece with the crotch portion.
A problem with absorbent articles of pants-like shape is that conventional articles of this kind tightly enclose the area around the genitals of the wearer, whereby this area, when body fluids are excreted, becomes locally saturated with moisture and vapor, which has an adverse effect on the skin of the wearer. In some cases disturbing skin irritation can occur. Furthermore, also minor chafing of the article against the skin of the wearer, in combination with a moist environment and during lengthy usage of the article, can give rise to sores on older people with flesh that heals poorly.
Breathable and vapor-permeable but liquid-impermeable materials for use in absorbent articles, such as diapers, incontinence products or sanitary towels, are previously known. Breathable materials can consist of perforated plastic films, as described in U.S. Pat. No. 5,628,737, or of micro-porous plastic films, as described in, for example, EP-A-0238200. Another example of breathable materials are so-called non-woven materials which are air-permeable and vapor-permeable and which, if required, have been treated with means to improve the liquid-impermeability, as is described in EP-A-0196654. In absorbent articles of pants-like shape, with a fit which tightly encloses around the wearer, the need for air-permeability and vapor-permeability is important. A further problem is that urine and other body fluids give rise to evil-smelling substances, such as ammonia and amines, which also cause a rise of pH. At high pH, the equilibrium is shifted for many smelly substances in such a manner that more volatile components are formed, and that, for this reason, they smell stronger than at a low pH.
An essential problem with absorbent articles of pants-like shape is that the demand for absorbent material is greatest where the space is the least, i.e., in the area directly in front of the genitals of the wearer. This in combination with all the above-mentioned problems associated with absorbent articles of pants-like shape has resulted in a great need to find a pants-like article which functions well in all respects and which, in addition, it is possible to manufacture rationally.